


reciprocity

by orphan_account



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Alternate Universe - Vampire, Blood, Blood Donation, Blood Drinking, Explicit Consent, Fluff, Guilt, M/M, Vampire Sherlock
Language: English
Status: Completed
Published: 2013-03-04
Updated: 2013-03-04
Packaged: 2017-12-04 07:39:58
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,678
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/708221
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: <blockquote class="userstuff">
              <p>"<b>Reciprocal altruism</b>, or reciprocity, is one solution to the evolutionary paradox of one individual making sacrifices for another unrelated individual. If individuals interact repeatedly, altruism can be favoured as long as the altruist receives a reciprocal benefit that is greater than its initial cost." - <i>Encyclopaedia Britannica</i></p>
            </blockquote>





	reciprocity

It had become something of a ritual, now.

Not the kind of ritual that required incense and chants and hooded robes— but the kind that began with John setting the water to boil and warming two mugs for tea. They talked, sometimes, about mundane things; Sherlock would be too tired to work up much of a deductive fervour. As often as not, they simply shared a companionable silence.

They both drank tea, even though John always asked Sherlock twice.

“You’re sure?”

Sherlock would nod.

He didn’t need a cup of tea, a cup of tea was probably rather unpleasant-- but he would drink it down in long, determined gulps. John wondered if it steadied him, like breathing exercises before a dive. Maybe it just passed the time.

Before they’d reached the dregs, the tension between them would be snapping and warm, like stretched rubber. It was a tension rather like the promise of sex, even though sex was rarely involved; the act was intimate enough. That didn’t mean they hadn’t tried and succeeded in mixing the two, in dangerous and decidedly upholstery-unfriendly ways, but their regular appointments, the necessary ones, usually ended in nothing more erotic than a long nap.

John rinsed his mug in the sink and went to close the blinds. The door to the flat was already locked.

“Yeah, well, what if he’d been wearing different colored socks?” he remarked.

“Don’t you see? It wouldn’t have made a difference at that point, so far to stage left, and I can hardly believe that a man who matches his cufflinks to his tie pin would have trouble telling black from navy blue.”

John smiled to himself, standing in the middle of the room and unbuttoning his shirt. Sherlock’s remarks were as incisive as they had been the day before-- but beginning to slur a little, like his movements. He looked and sounded like he was moving through a substance thicker than air.

John pulled off his shirt and draped it over the edge of a chair. He sat down on the couch and made himself comfortable. Sherlock paced around the kitchen, still gripping his mug.

“Come on, then,” John said quietly. He always had to say something, even if it was only a meaningless word or two.

Sherlock set the mug down without looking at him and slipped of his jacket.

The first time John had asked, “ _Why don’t you take off your shirt?_ ” Sherlock had rolled his eyes like an adolescent being reprimanded for not tucking a napkin down his front. This had been a mistake, and one he hadn't repeated.

Stripped to the waist, Sherlock stood facing the mantlepiece and fidgeting.

“Come on,” John said again, more softly still. He was half-reclining, hands settled in his lap.

Sherlock paced the room once more before coming to sit beside him. They sat like that for a while, shoulder to shoulder. Sherlock stared straight ahead, and John watched his fingers curl and uncurl. This behavior wasn’t anything out of the ordinary, but John settled a reassuring hand on the thigh pressed against his, all the same.

A breath whistled from between clenched teeth, and Sherlock rolled onto his side. He tucked his forehead between John’s neck and shoulder, and John could feel each panting breath against his skin.

“Alright?” John asked. He felt the nest of curls nod yes.

One long arm looped over John’s bare chest, and wiry fingers gripped his shoulder.

“Alright?” Sherlock asked, and his voice was a scrape of gravel.

“Mm.” John curled an arm to rest his fingertips on Sherlock’s neck. He could feel him trembling, an electric buzz transferred from skin to skin, his whole body vibrating with strained control.

Sherlock’s lips brushed over John’s scarred shoulder, over his clavicle, restless, finally settling over his pectoral. John’s muscles clenched, but only briefly; a steadying breath, and his upper body went slack.

“I trust you,” he murmured, and that was a part of the ritual, too.

The flat arc of Sherlock’s teeth ( _maxillary central incisors, maxillary lateral incisors, maxillary canines_...) pressed against his skin and John thought about the man with the matching cufflinks and tie pin and whether there was anything more to that deduction that he was missing, there probably was, there usually was, and he thought hard enough about the strange color of the man’s tie that he didn’t flinch when maxillary haemophilic canines punched through his flesh.

There was a tug, not too painful, like retreating needles or an un-snagged thorn, and then a soft squelch of saliva against the wounds.

“ _Morphological peculiarities,_ ” Sherlock had muttered, staring at his own saliva under a microscope. Hirudin and desmoteplase, beautiful words that meant torn capillaries and veins that flowed without clotting.

Sherlock bit again, a few inches higher. Blood trickled from the first puncture, untasted.

John stared at the ceiling and concentrated on keeping still. Sherlock released his snakebite hold and drew back with a gasp. John wound dark curls around his fingers and breathed deeply. Blood trekked little crooked paths over his ribs.

Their first encounter after the change had been an accident. It didn’t bear reminiscing. Once it was clear that John would recover, Sherlock had locked himself in 221C, spinning a cocoon of guilt and shame and frustrated intellect that could not be penetrated by forgiveness or entreaties.

So John broke down the door. They fought. John’s position— which, he emphasized, was _always_ his position, no matter the diet in question— was that Sherlock needed to eat more frequently. Sherlock insisted on self-discipline. John suggested he try holding his breath until he stopped needing oxygen.

Sherlock’s needs were straightforward; but his _instinct_ , as the accident had made all too clear, was to bite and keep biting. He should have been able to bite once and drink and have done with it. Anything else was a pointless excess— an insult to the elegance of evolution. But no matter how often or how angrily Sherlock expressed his opinion, his body would not yield. “ _We’ll just have to coordinate,_ ” John had said, and that was the end of it.

John was patient and Sherlock unyieldingly willful. After a few months of experimenting, John no longer kept a syringe of Acepromazine on standby. A few months more, and the sessions were almost routine.

John let slip a soft, “ _Ah_ ,” at the third bite. It hurt— piercing too close to shoulder muscle and bone.

Sherlock arched his back and pressed both palms hard against John’s forearms, half-straddling his legs, caught between pinning the other man down and pushing himself backward and away.

“It’s okay,” John exhaled. “It’s okay.”

With the hand that wasn’t tangled in murky curls, he coaxed Sherlock’s vice-grip on his bicep to loosen, and laced their fingers together. His torso was cherry-striped, blood pooling in soft creases of skin.

“Drink.”

Sherlock wouldn’t look at him, but John knew from past encounters that his pupils were swollen into full stops, dark and huge. He stroked back messy fringe and glimpsed parted lips, glistening and red.

“Drink,” he murmured.

Sherlock lowered his head, shakily, as if pushing against a heavy weight. He lapped in long, hot smears of tongue, searching out every dip and hollow where John’s blood collected, then leaned up to lick beneath each throbbing puncture.

John felt a familiar lightheadedness, and closed his eyes. His senses were all a-jumble, pleasure and ache sliding together. He let his hand fall from Sherlock’s head, cupping his palm against his own belly to catch a stray crimson rivulet. When the wrinkles and lines were puddled with red he lifted it to Sherlock’s questing mouth.

_Don’t waste it._

Sherlock hesitated, then nuzzled into the crooked fingers. John felt his tongue slipping between each knuckle, slicking a figure eight against his palm. He brushed his thumb against Sherlock’s cheek. _It’s okay. Don’t be ashamed._

John was beginning to feel grey behind the eyes, and glanced toward the clock. Sherlock shifted, half cradling him, now. He worked to mend the punctures, the texture of his saliva subtly changed. They must look like a painting, the pair of them; a medieval allegory.

John closed his eyes.

He wasn’t sure how much time had passed when he became dimly aware of something warm and good rubbing circles against his skin. He opened his eyes and saw Sherlock’s hand— not trembling now, but steady— drawing a damp cloth over his chest. He was dressed again, and kneeling at John’s feet with a steaming mug, where he dipped the cloth when it grew cool. He squeezed clean water over the dip at John's collarbone and let it run down his chest, catching the drips and brushing the cloth over each rib in turn, gentle and thorough.

John swallowed, and found it difficult to speak.

“Quiet,” Sherlock said.

When he was finished, he stood, without looking at John, and carried the mug and the cloth to the sink. He returned with a tall glass of something pink, which he pressed into John’s hand.

John sipped, fizziness surprising his throat, watching Sherlock’s face. When he had emptied the glass, Sherlock took it from him and set it aside. Then he curled up next to John and laid his head in his lap.

“Thank you,” John said, brushing his hand over the eyes that refused to meet his.

There was a long silence, and John was almost drowsing when he heard a muffled, “Twenty-seven."

“Hm?”

“Twenty-seven,” Sherlock repeated. “Pints. That’s how much of mine you’re owed.”

John blinked, then cupped an angular cheek to turn Sherlock’s gaze toward his.

“Sherlock— are you talking about your blood?”

Sherlock's eyes were nearly back to normal, pupils dilated but showing a ring of pale blue.

“Yes.”

“You know that’s more than twice what the human body—”

“It doesn’t matter.” Sherlock’s mouth pressed into a determined line. “It’s still yours.”

John couldn’t help himself, and leaned down to kiss him— just a brush of lips, smile hiding in the corners.

“If it’s mine,” he said, “then you had better take good care of it.”

**Author's Note:**

> This ficlet was originally posted to [netherworldvineyard](http://netherworldvineyard.tumblr.com/) on tumblr. This is my first completed work for the Sherlock fandom and my first publicly posted fanfiction, so comments are much appreciated! Thanks to [cypress_tree](http://cypress-tree.tumblr.com/) for being my first-looker.


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